According to what you are saying that would make John the baptizer a person of impurity for he told people to repent of their sins. John spent much of his time baptizing people and hearing their sins. Your reasoning makes John the baptizer a sick impure person.
You have no idea what it meant for them to be "confessing their sins". It wasn't John listening to their list of sins (he'd still be there). It was them being identified in water!
Matthew 3:1 In those days came John the Baptist, preaching in the wilderness of Judaea,
Matthew 3:2 And saying, Repent ye: for the kingdom of heaven is at hand.
Matthew 3:3 For this is he that was spoken of by the prophet Esaias, saying, The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight.
Matthew 3:4 And the same John had his raiment of camel's hair, and a leathern girdle about his loins; and his meat was locusts and wild honey.
Matthew 3:5 Then went out to him Jerusalem, and all Judaea, and all the region round about Jordan,
Matthew 3:6
And were baptized of him in Jordan, confessing their sins.
It was a baptism of repentance for the remission of sins! Look at it!
Mark 1:1 The beginning of the gospel of Jesus Christ, the Son of God;
Mark 1:2 As it is written in the prophets, Behold, I send my messenger before thy face, which shall prepare thy way before thee.
Mark 1:3 The voice of one crying in the wilderness, Prepare ye the way of the Lord, make his paths straight.
Mark 1:4
John did baptize in the wilderness, and preach the baptism of repentance for the remission of sins.
Mark 1:5
And there went out unto him all the land of Judaea, and they of Jerusalem, and were all baptized of him in the river of Jordan, confessing their sins.
